1. Field of the Invention
The present invention relates to a voice start recording apparatus and, more particularly, to a voice start recording apparatus which automatically starts/stops a recording operation in response to predetermined voice.
2. Related Art Statement
In recent years, there is provided a recorder in which a voice signal obtained by a microphone or the like is converted into a digital signal, the digital signal is stored in, e.g., a semiconductor memory, the voice signal is read from the semiconductor memory to be converted into an analog signal in a reproducing operation, and the analog signal is outputted as voice by a loudspeaker or the like. Japanese Unexamined Patent Publication No. 63-259700 discloses an example of the recorder described above.
In the general recorder type described above, in order to save an amount of data recorded on the semiconductor memory, an amount of generated data is decreased as much as possible by performing high-efficient coding to a digital voice signal.
There is also provided a scheme of performing a compressing process to a silent portion to obtain the high efficient coding. It is generally known that general dialogue includes a silent portion, and that a bit rate can be decreased by about 30% by compressing the silent portion.
As a voice recording apparatus, e.g., a tape recorder for conference recording, a recorder which automatically starts a recording operation in response to voice and stops the recording operation a predetermined period of time after the voice is interrupted is known. In a recording standby state, when such a recorder receives voice having a predetermined start level (adjustable by a user), the recorder starts a recording operation. When the input voice has a level lower than the predetermined level, the recorder stops the recording operation 3 to 4 seconds later.
More specifically, when voice having a level equal to or higher than the predetermined start level, the recorder determines that "sound" is set to start a recording operation; when the input voice has a level lower than the predetermined level, the recorder determines that "silence" is set to stop the recording operation.
However, in the recorder described above, the following drawbacks occur. That is, a recording operation is erroneously started by environment noise such as sound generated by opening/closing a door or coughs, and the recorder cannot be stopped when the recorder must be stopped because of external noise. In addition, a leading portion is disadvantageously cut at the start of a recording operation.
In the voice recording apparatus comprising an automatic voice starting function, a start/stop level of a recording operation is fixed in the apparatus itself, or a user must operate a volume or a sensitivity switching switch to set the level to be a desired start level in advance.
However, a means for setting the start/stop level cannot easily set a proper level by catching input voice which always changes, and the start level must be sought after a trial recording operation is performed.
In the above voice start recording apparatus, as a setting switch to operate the voice start recording function, a devoted operation member must be arranged. If the devoted operation member is not used, a setting switch having a rapid hearing reproducing function or the like is also used as the set switch for the voice start recording function. In this case, a predetermined operation must be performed to operate the voice start recording function.
However, when devoted operation members corresponding to the functions described above are independently arranged, the apparatus itself increases in size, and the increase in size of the apparatus limits a compact design. In addition, workability in an assembling operation is degraded with an increase in the number of members, and manufacturing costs may disadvantageously increase.
When the operation member or the like for the voice start recording function is also used as an operation member for another function, in use of the apparatus, the operability of each operation member is degraded.
When the operation member or the like for the voice start recording function is also used as an operation member for another function, in general, a general contact-fixed type mechanical slide switch or the like is generally applied. In this case, unless an operation such as a mode switching operation is performed, the recording apparatus is fixed to a mode state set by the above operation member or the like.
Therefore, when use of the above recording apparatus or the like is to be started by another set mode but a set mode set when the apparatus is previously used, a switching operation or the like is performed prior to the start of use, and a switching operation to a desired set mode must be performed. That is, a preparing operation before use of the recording apparatus is started is disadvantageously cumbersome.